Add option to read grpc-secret from file (#1972)

cmd/server/flags.go

@@ -108,6 +108,7 @@ var flags = []cli.Flag{
 		Name:     "grpc-secret",
 		Usage:    "grpc jwt secret",
 		Value:    "secret",
+		FilePath: os.Getenv("WOODPECKER_GRPC_SECRET_FILE"),
 	},
 	&cli.StringFlag{
 		EnvVars: []string{"WOODPECKER_METRICS_SERVER_ADDR"},

docs/docs/30-administration/10-server-config.md

@@ -270,6 +270,11 @@ Configures the gRPC listener port.
 
 Configures the gRPC JWT secret.
 
+### `WOODPECKER_GRPC_SECRET_FILE`
+> Default: empty
+
+Read the value for `WOODPECKER_GRPC_SECRET` from the specified filepath.
+
 ### `WOODPECKER_METRICS_SERVER_ADDR`
 > Default: empty